EMB,L6 22-10-2023pdf.pdf

EMBRYOLOGY6 Dr.Ban A.Ghani DEVELOPMENT OF PALATE AND ANOMALIES Mammalian palatogenesis is a highly regulated process involves the initiation, growth, morphogenesis and fusion of the primary and secondary palatal shelves (from initially separate facial...

EMBRYOLOGY6 Dr.Ban A.Ghani DEVELOPMENT OF PALATE AND ANOMALIES Mammalian palatogenesis is a highly regulated process involves the initiation, growth, morphogenesis and fusion of the primary and secondary palatal shelves (from initially separate facial prominences during embryogenesis to form the intact palate separating the oral cavity from the nostrils).It develops as outgrowths from the medial nasal and maxillary prominences, respectively, remodel and fuse to form the intact roof of the oral cavity. THE SECONDARY PALATE The secondary palate develops as bilateral outgrowths from the maxillary processes, the palatal shelves initially growing vertically behind the primary palate and lateral to the developing tongue. Subsequently reorient to the horizontal position above the dorsum of the tongue in a process known as palatal shelf elevation. With growth and expansion of the mandible the tongue moves down, allowing the palatine shelves to grow toward the midline where they meet and fuse with each other. The secondary palate fuses anteriorly with the primary palate with the incisive foramen being the landmark between the primary and secondary palate,and anterodorsally with the nasal septum, to form the intact roof of the oral cavity. EMBRYOLOGY6 Dr.Ban A.Ghani THE PRIMARY PALATE The primary palate arises from the intermaxillary segment.Tpalatehe primary will form the premaxillary portion of the maxilla.This small portion is anterior to the incisive foramen and will contain the maxillary incisors. EMBRYOLOGY6 Dr.Ban A.Ghani THE PALATINE UVULA It’s a little piece of teardrop-shaped tissue that hangs from the back of the roof of the mouth. During swallowing, the soft palate and the uvula move together to close off the nasopharynx, so helps prevent food and liquid from from entering the nasal cavity during swallowing. It also secretes saliva to keep mouth hydrated. The uvula is also part of gag reflex. When something touches this area of soft palate, it could induce gagging or vomiting as a safety feature. If uvula senses that something is going down the “wrong way,” it course corrects in an effort to avoid choking. FACIAL ANOMALIES Complete fusion of the primary and secondary palate is a complex process involving growth of the component tissues, epithelial to mesenchymal transformation, cell migration, and programmed cell death at fusion sites Disruption of any part of this process can result in cleft palate. Craniofacial anomalies are deformities that affect a child's head and facial bones. These disorders are typically present at birth (congenital) and can range from mild EMBRYOLOGY6 Dr.Ban A.Ghani to severe. Common craniofacial anomalies include: cleft lip and palate: a separation in the lip and the palate. CLEFT LIP AND CLEFT PALATE Cleft lip and cleft palate are facial and oral malformations that occur very early in pregnancy, while the baby is developing inside it’s mother. Clefting results when there is not enough tissue in the mouth or lip area, and the tissue that is available does not join together properly. CLEFT PALATE Is a split or opening in the roof of the mouth. A cleft palate can involve the hard palate, and/or the soft palate Cleft lip and cleft palate can occur on one or both sides of the mouth. Because the lip and the palate develop separately, it is possible to have a cleft lip without a cleft palate, a cleft palate without a cleft lip, or both a cleft lip and cleft palate together. CLEFT LIP Is a physical split or separation of the two sides of the upper lip and appears as a narrow opening or gap in the skin of the upper lip. This separation often extends EMBRYOLOGY6 Dr.Ban A.Ghani beyond the base of the nose and includes the bones of the upper jaw and/or upper gum. HARE LIP A congenital cleft or fissure in the midline of the upper lip, resembling the cleft upper lip of a hare, often occurring with cleft palate.Result from bilateral failure of fusion of maxillary and medial nasal prominences. OBLIQUE FACIAL CLEFT Unilateral failure of maxillary and lateral nasal prominences to fuse. MACROSTOMIA Incomplete lateral merging of maxillary and mandibular processes. HEMIFACIAL MICROSOMIA A condition in which the tissues on one side of the face are underdeveloped MICROSTOMIA Two much fusion of mandibular and maxillary prominances may result in small mouth FRONTONASAL DYSPLASIA Hyperplasia of inferior frontonasal prominence ,thus preventing fusion of the medial nasal prominenses. Bilateral macrostomia Oblique facial cleft frontonasal dysplasia EMBRYOLOGY6 Dr.Ban A.Ghani